N324ST – Piper Aircraft Corp PA-32R-301 – 2007-03-24 NTSB Accident Report

HISTORY OF FLIGHT

On March 24, 2007, about 0920 eastern daylight time, a Piper PA-32R-301, N324ST, was destroyed when it impacted terrain following a loss of control while maneuvering near Jacksonville, Maryland. The certificated private pilot and two passengers were fatally injured. Instrument meteorological conditions (IMC) prevailed for the flight that departed Harford County Airport (0W3), Churchville, Maryland, about 0906, destined for Virginia Highlands Airport (VJI), Abingdon, Virginia. An instrument flight rules (IFR) flight plan was filed for the personal flight conducted under 14 Code of Federal Regulations (CFR) Part 91.

According to transcripts provided by the Federal Aviation Administration (FAA), the accident pilot contacted the Williamsport Automated Flight Service Station via telephone on the day prior to the accident to obtain a weather briefing and to file an IFR flight plan. During the briefing, the pilot indicated that he was going to fly to VJI so that he could attend a NASCAR race in Bristol, Tennessee.

The next morning, the pilot contacted Potomac Terminal Radar Approach Control (TRACON) to obtain his IFR clearance. At 0858, the pilot was given a clearance and was told that the clearance would be void at 0908 (10 minutes). The pilot acknowledged. Eight minutes later the pilot departed and contacted Potomac TRACON shortly after departure.

The airplane’s Avidyne Entegra flight deck instrumentation was capable of recording some flight data and other parameters. Safety Board investigators downloaded these data, and compared them to air traffic control (ATC) recorded radar and voice data provided by the FAA. The flight deck instrumentation data revealed that the Primary Flight Display's (PFD) Attitude Heading Reference System (AHRS) had failed to align twice on the day of the accident; once on the electrical power cycle preceding the accident flight, and again when the PFD was started up for the accident flight.

According to Avidyne, if the PFD is not aligned, then heading data, Horizontal Situation Indicator (HSI) navigation data, and attitude data are removed from the display and replaced with Red “Xs". The PFD also cannot be used to control the autopilot computer, limiting the available functionality of the autopilot. The PFD would still however, display altitude, airspeed, and vertical speed.

According to the recorded data, prior to takeoff, the vertical speed “bug” on the PFD was set at 750 feet per minute (fpm). The airplane then took off, maneuvered to a westerly heading on track to the Westminster VOR, and at 09:06:37 established an indicated climb rate of about 450-500 fpm. At 09:07:11, the airplane was at an altitude of about 1,440 feet msl and ATC instructed the pilot to climb and maintain 8,000 feet. The PFD altitude bug changed from 5,000 to 8,000 feet. At 09:08:24, the airplane was at an altitude of about 2,000 feet msl and ATC asked “verify you are climbing”. The pilot responded with “say again please.” ATC replied, “climb and maintain eight thousand,” which the pilot acknowledged.

At 09:08:37, the data indicated that the PFD’s vertical speed bug setting changed from 750 fpm to 950 fpm. About 09:09:24, the setting increased to 1,050 fpm. At the same time, the pitch attitude reversed its downward trend to an upward trend. About 16 seconds later, a vertical speed was established at about 1,100-1,200 fpm, which lasted for approximately 43 seconds. During this 43-second period, the pitch attitude continually increased at a relatively constant rate, and airspeed decreased at relatively constant rate from about 115 knots to about 94 knots.

Also during this 43-second period, the vertical speed bug setting reduced twice; first to 850 fpm and once again to 750 fpm. However, the vertical speed remained at 1,100-1,200 fpm. After this period, the vertical speed began to fluctuate, at times reaching peaks of 5,000 fpm down, and 7,500 fpm up. The fluctuation continued until the end of the recording. Altitude, pitch attitude, airspeed, and vertical acceleration also continued to fluctuate until the end of the recording, with trends consistent with the vertical speed trend.

Twenty seconds after the vertical speed fluctuations began, at about 09:10:53, the airplane began the first of three 360-degree turns to the left. As the turn began, the trend of roll attitude was initially to the left followed by a reversal and brief trend to the right before reversing again and remaining left wing down (though oscillating in value) for the duration of the 3 “orbit” turns to the left. During these turns, the vertical speed, airspeed, and pitch and roll attitudes continued to fluctuate. About halfway through the set of turns, at 09:12:15, the pilot transmitted to ATC: “we seem to be having some type of difficulty here could uh you give us assistance please”.

At 09:13:01, after the airplane completed the three turns, the pilot transmitted: “we’re with ya we were off getting back on course here we had a little difficulty with the auto pilot.” At this time, the airplane’s track was approaching its original course line to the Westminster VOR. At 09:13:35 the pilot requested a heading to the Frederick airport, so they could “do a stop”, and he received a clearance to fly a heading of 280 degrees. Also over the next 30 seconds, the airplane’s track stabilized at about 274 degrees magnetic. Altitude and airspeed continued to fluctuate during this time; however the pitch attitude was relatively stable when compared to the previous and subsequent pitch oscillations.

At 09:14:08, the airplane again began a turn toward the left. At 09:14:46 the “next waypoint” parameter changed from EMI (the Westminster VOR) to KFDK (Frederick Municipal Airport). At 09:15:23, the pilot again reported to ATC that he was “having some problems with the autopilot”. After the left turn, the airplane did not return to a course toward Frederick, and did not maintain any course/heading for longer than about 12 seconds. Altitude and airspeed continued to fluctuate significantly, with the exception of one period of about 20 seconds where the altitude was relatively stable around 2,600 feet (pressure altitude) and the airspeed remained around 110 knots. Over the last 2 minutes of the flight, the fluctuations in altitude and airspeed appear to be somewhat periodic in nature.

The last recorded data points indicated a pressure altitude of 707 feet, indicated airspeed 148 knots, and a descent rate of 6,824 fpm.

AIRCRAFT INFORMATION

According to FAA and airplane maintenance records, the accident airplane was manufactured in 2006. The airplane’s most recent annual inspection was completed on March 1, 2007. At the time of the inspection, the airplane had accrued 74.9 total hours of operation.

The airplane was equipped with an Avidyne FlightMax Entegra Integrated Flight Deck, which included two 10.4-inch displays, one of which was the PFD and the other of which was the Multi Function Display (MFD).

A set of standby flight instruments were also installed which consisted of a magnetic “whiskey” compass (attached to the center post of the windscreen), a conventional attitude indicator, conventional airspeed indicator, and a conventional altimeter (all of which were located to the left of the PFD in a vertical line). All could be used by the pilot to fly the airplane in instrument meteorological conditions in the event that the PFD malfunctioned.

Additionally, the airplane was equipped with dual Garmin GNS 430 global positioning systems (GPS), and an S-TEC System 55X autopilot, with full-function heading, navigation, and altitude hold, with localizer/glideslope coupling, and altitude pre-select functions that were integrated into the PFD. Together with the audio control panel, these systems were located to the right of the PFD in a vertical line.

During the most recent annual airworthiness inspection, maintenance personnel determined that the accident airplane required modification of the PFD as required by Avidyne's PFD Mandatory Service Bulletin, SB 601-00006-067. This bulletin referenced earlier alerts and requested that the PFDs be returned to the factory for an update which would “reduce the likelihood” that the PFD could present erroneous indications. According to an FAA inspector and the maintenance provider’s Director of Service , the maintenance facility was advised by the pilot that due to the amount of time required to update the unit (10 business days), and since the pilot was trading in the airplane soon, the pilot elected to defer the maintenance action until a later date.

PERSONNEL INFORMATION

According to FAA records, the pilot held a private pilot certificate with ratings for airplane single-engine land, and instrument airplane. His most recent FAA third-class medical certificate was issued on December 12, 2006. The pilot records also indicate that the accident airplane was the second Avidyne-equipped airplane the pilot had owned; the first airplane that he owned was a Piper PA-32-301FT. The pilot also had taken formal training at Simcom when he purchased his first Avidyne equipped airplane, and again when he purchased the accident airplane. He had accrued 546.2 total hours of flight experience of which 291.5 hours were accrued in the two airplanes. At the time of the accident, records indicated that he was IFR current and qualified.

METEOROLOGICAL INFORMATION

The recorded weather at Martin State Airport (MTN), Baltimore, Maryland, approximately 26 nautical miles southeast of the accident site, at 0918, included: wind 020 degrees at 3 knots, visibility 3 miles in heavy drizzle, scattered clouds at 800 feet, broken clouds at 2,400 feet, overcast at 3,000 feet, temperature 8 degrees C, dew point 8 degrees C, and an altimeter setting of 30.36 inches of mercury. Cloud tops were reported to ATC by a Southwest Airlines flight as being at 8,500 to 9,000 feet above mean sea level (msl). Witnesses reported that the cloud bases were low to the ground and it was raining.

WRECKAGE AND IMPACT INFORMATION

The wreckage was located in a residential area about 17 miles west of 0W3. Examination revealed that all major components of the airplane were located at the accident site. After impacting trees, the airplane came to rest on a magnetic heading of 216 degrees. An approximately 3-foot deep crater existed beneath the main wreckage. An 85-foot long debris field, oriented on a magnetic heading of 212 degrees was present. Multiple portions of tree limbs, exhibiting cut marks consistent with propeller strikes, were spread throughout the area.

The engine and propeller remained attached to the airplane but were buried below ground level. All three propeller blades exhibited evidence of rotation. One blade was separated from the propeller hub approximately 1-inch outboard of the blade grip. A partial disassembly and examination of the engine did not reveal any evidence of preimpact mechanical malfunction.

All passenger entry and baggage door latches were in the closed position. Both the landing gear and the flaps were in the up position. The fuel selector valve was in the left tank position. The standby attitude indicator indicated a 60-degree right bank, a 20-degree nose down pitch attitude, and evidence of rotational scoring internally. The barometric scale on the standby altimeter indicated 29.65 inches of mercury. The airspeed indicator was off-scale above 215 knots.

Both wings were separated from their mounting locations and exhibited fracturing and various degrees of crush damage. The wing flaps and ailerons exhibited multiple breaks and separations and were spread throughout the debris field. The vertical stabilizer and rudder panel remained attached to their fittings. The left and right portions of the stabilator were fragmented. The center portion of the stabilator, portions of the right side anti-servo tab, and stabilator actuation mechanism remained attached to the aft fuselage.

The pitch trim jackscrew was found in the full nose-down position, however; no preimpact failures or disconnects of the primary flight control system were discovered. Control continuity was established from the stabilator control mechanism to the control wheel pitch actuating mechanism; the rudder pedals to the rudder panel, and from the ailerons to the broken ends of the control cables, which exhibited evidence of tensile overload.

MEDICAL AND PATHOLOGICAL INFORMATION

A postmortem examination was performed on the pilot by the State of Maryland’s Office of the Chief Medical Examiner. Toxicological testing of the pilot was conducted at the FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma. The pilot's forensic toxicology report revealed that, ethanol was detected in Muscle (from sources other than ingestion), and Naproxen which is a non-steroidal-anti inflammatory drug, was detected in Liver.

TESTS AND RESEARCH

Component Tests

Because the pilot advised ATC that he “had a little difficulty with the autopilot”, and the pitch trim jackscrew was found in the full nose-down position, both the autopilot control system, and pitch trim system, were examined. No evidence of any pre-impact malfunctions was discovered.

If an autopilot malfunction had occurred, the pilot could have disconnected the autopilot system by any one of the six following actions: Pressing the AP DISC/TRIM INTR switch on the control yoke; Actuating the electric trim via the Trim Switch; Turning off the AP Master Switch; Pulling the AP Circuit Breaker; Turning off the Avionics Master switch; Turning off the Battery Master Switch.

Because the autopilot computer received analog information from the PFD, investigators reviewed the differences between the interaction of the autopilot with an aligned PFD and an unaligned PFD. The review revealed that when the PFD is aligned, it provides the autopilot with the analog Vertical Speed Indicator (VSI) “bug” value set on the PFD and that the autopilot computer utilizes this value as a target when operating in either the vertical speed (VS) mode or the altitude capture mode. When the PFD is not aligned, the VSI “bug” on the PFD is visible and can be adjusted, but the PFD will only output a value of zero, along with a discrete flag, resulting in the autopilot (instead of the PFD) being in control of the vertical speed target. In this condition, the autopilot’s VS mode will attempt to hold the current vertical speed at the time the mode is activated, and the desired vertical speed would have to be adjusted using a separate knob on the autopilot control panel. A review of the Entegra Piper PA28 and PA32 EXP5000 Primary Flight Display Pilot's Guide revealed however, that it did not provide this information to the pilot regarding suppression of the bug settings when the PFD was not aligned.

A turn coordinator provided the S-TEC 55X autopilot flight guidance computer with signals indicating the airplane’s turn and roll rate. Examination of the wreckage revealed that the turn coordinator was installed forward of the instrument panel where it was not visible to the pilot; therefore, the turn coordinator could not be utilized by a pilot in the event of a failure of the PFD, or used to help determine the airplane’s attitude if there was a disagreement between the displayed attitude on the PFD and the standby attitude indicator. FAA certification standards for glass panel equipped aircraft like the accident airplane do not require a turn coordinator. Examination of other manufacturer’s airplanes configured with a single PFD also revealed similar configurations with non-viewable turn coordinators. Examination of the turn coordinator did not reveal any evidence of a pre-impact failure or malfunction.

The Air Data Unit (ADU) supplied the following air data to the Air Data and Attitude Heading Reference System (ADAHRS): Pressure Altitude, Calibrated Airspeed, True Airspeed, Outside Air Temperature (OAT) and Vertical Speed.

Internal examination of the ADU’s pressure transducers revealed no anomalies and the pressure altitude data recorded by the PFD agreed with the pressure altitude in the recorded radar data.

Magnetometer

The Avidyne magnetometer/outside air temperature (OAT) sensor assembly was used to measure the strength and direction of the magnetic field in three axes and for measuring the outside air temperature. It incorporated a high sensitivity three-axis magnetic sensor assembly and processing elements in a sealed mounting container and an external temperature-sensing element mounted inside the right wing near the wingtip of the accident airplane. It would supply three axis magnetic field and OAT data over a serial line to the PFD.

Accident Magnetometer Examination and Testing

The connector and pigtail were replaced using approved Avidyne procedures. The magnetometer was tested with no anomalies observed. Proper alignment was achieved when the unit was connected to a PFD. However, heading errors of 31 and 63 degrees were noted. According to Avidyne, the approved repairs necessary to patch up the damaged connection cable from the accident magnetometer would have corrupted the calibrated state of the magnetometer, thus failing the post-accident test.

The magnetometer was examined at the U.S. Air Force Research Laboratory (AFRL). They found several areas of concern such as: a sensor chip that was retained by the use of sockets with little retention force and without retention mechanisms, black residue and fretting corrosion at the socket pins, the chips pins were solder coated while the sockets were gold coated, wires were soldered directly to the circuit boards, high wattage resistors squeezed into close proximity, and solder balls throughout the area (one was bridging two leads).

Additional details are provided in the docket of NTSB Case No. NYC07FA083. The report title is “Magnetometer Examination and Testing.”

Vero Beach Ground and Flight Testing

On January 28 and 29, 2008, the NTSB conducted ground and flight testing on an exemplar Piper PA-28-181 airplane configured similar to the accident airplane. Testing was conducted on the airplane’s autopilot system, PFD, and the accident airplane’s magnetometer. It took 4 minutes and 50 seconds for investigators to complete the autopilot manufacturer’s preflight procedures that were published in the System Fifty Five X Autopilot Pilot's Operating Handbook (POH). One step of the autopilot preflight procedures listed in the POH required that the pilot move the heading bug as part of the test. The recorded data from the accident flight showed however, that the heading bug did not change until after the airplane had taken off.

The accident autopilot could not be tested because of impact damage. Testing of its available components did not reveal any anomalies.

Testing of the exemplar PFD revealed that if a power interruption occurred following successful AHRS alignment, and the PFD was powered back up within 15 to 20 seconds of the interruption, the PFD would go through a quick restart and resume normal operation. However, if the power interruption exceeded 15 to 20 seconds it would not perform a quick restart, and would require a normal alignment procedure (including remaining stationary at the appropriate times) in order to function properly. It was also observed that if the PFD lost communication with the magnetometer, the attitude data, heading data, and HSI navigation data would “X” out. If the airplane was yawed during the initial AHRS alignment period (consistent with the PFD power cycle prior to the accident flight) the AHRS would never align, and the red “Xs” would remain displayed on the PFD.

PFD Startup and Alignment Process

According to the Avidyne EXP5000 PFD Pilot’s Guide, in order to start the PFD, the ADAHRS system required an alignment time before the airplane was ready for flight. The PFD was designed to operate during engine start and shut down, and startup was automatic once power was applied via the battery switch. The pilot’s guide advised that a common startup procedure was to turn on the battery and conduct the aircraft preflight during the ADAHRS alignment process, and that “The PFD and ADAHRS alignment process may restart when you start the engine.”

If the PFD is not aligned, then heading data, HSI navigation data, and attitude data are removed from the display and replaced with Red “Xs”. The pilot’s guide also advised that typical alignment time was 3 minutes, but could take longer if the aircraft was subjected to motion.

A note stated: “For faster alignments (3 minutes or less) Avidyne recommends that you do not move the aircraft until alignment is complete. The OK TO TAXI message provides increased flexibility during ground operations, but may extend overall alignment time.”

The alignment of the AHRS system consists of three different phases:

(1) In the first phase, “Initial AHRS Alignment”, the basic operating parameters of the inertial sensors (accelerometers and rate gyros) were measured. During this phase, it is critical to the alignment process that the airplane remains stationary. Specifically, in PFD log time the critical period that the airplane must remain stationary is during Time =22 to 36 seconds.

(2) In the second phase, “AHRS warming up”, the sensors were allowed to come to their normal operating condition as their operating parameters were monitored. If the airplane is stationary during this phase, it will take about 90 seconds to complete. However, for pilot convenience, the airplane may taxi during this phase.

(3) In the final phase, “Final AHRS alignment”, inertial "down" and "north" vectors are determined with regard to the operational sensors. Once again, the airplane must remain stationary during this phase.

The pilot’s guide also advised that while alignment and startup should proceed smoothly, in the case of error, the pilot may see one of a number of AHRS alignment error messages in the AHRS initialization box, which would advise the pilot that the unit was “UNABLE TO COMPLETE ALIGNMENT.”

According to Avidyne, once power was applied to the PFD, the “Initial AHRS Alignment” message box would be displayed on the screen. As was stated in the Avidyne PFD pilot’s guide, the AHRS system required an alignment time of approximately three minutes; however, it could take longer if the system detected that the airplane was in motion. According to Avidyne, if aircraft motion was sensed during certain alignment phases, the inertial parameters must again settle and the final alignment timer would be reset to a minimum of 45 seconds.

During the flight testing at Vero Beach, it was discovered that when the PFD fails to align (either due to motion during the critical alignment period, or due to takeoff before alignment process completes), at the end of the alignment procedure, the startup message box would indicate “UNABLE TO COMPLETE ALIGNMENT - MOTION SENSED – STOP AIRCRAFT Alignment Should Resume Within 2 mins”.

It was also discovered that, if the airplane had previously moved during the INITIAL alignment phase, the PFD would start the alignment process over again and cycle through each alignment phase and message sequence, and repeat, indefinitely. This would occur even if the airplane were stopped after the UNABLE TO COMPLETE ALIGNMENT message.

Also, if the airplane was moving during the “INITIAL or the “FINAL” phases of the alignment sequence, there was no immediate indication that motion was sensed, and the alignment process would appear to continue normally until the final alignment phase, during which the message “UNABLE TO COMPLETE ALIGNMENT- MOTION SENSED – STOP AIRCRAFT Alignment Should Resume Within 2 mins” would appear.

This behavior was observed on the ground, when the airplane was intentionally moved during the critical INITIAL AHRS ALIGNMENT phase only, and kept stationary thereafter. It also occurred if the airplane was kept stationary during the INITIAL phase, and then began taxiing during the “OK TO TAXI” phase, and continued motion all the way through takeoff (not stopping for the FINAL phase) and the process would continue to repeat for the remainder of the flight.

Furthermore, it was observed that the unit would not transition from the “FINAL AHRS ALIGNMENT” screen if the airplane was moved. The screen would display “FINAL AHRS ALIGNMENT, REMAIN SATATIONARY, READY TO GO IN X SECONDS” where the maximum time would be 45 seconds and counting down. However, the process would simply repeat and full alignment would never be achieved.

MFD and PFD Non-volatile Memory

Examination of the MFD revealed that it had sustained significant damage; however, the compact flash (CF) memory card was readable. All data was successfully extracted. Although the MFD data logs did not contain any MFD diagnostic or maintenance parameters, the MFD data (primarily engine performance parameters) appeared to be normal.

The PFD sustained significant impact damage. It contained two flash memory devices that were successfully downloaded at Avidyne’s facility using a surrogate PFD. The PFD recording contained the accident flight’s power cycle. The duration of the 38th power cycle was approximately 21 minutes; the accident flight from the start of the takeoff roll until the end of the data was approximately 14 minutes 46 seconds. The MFD recording contained the accident flight’s power cycle, which was approximately 20 minutes in duration.

The data further showed that the AHRS had failed to align twice on the day of the accident; once on the electrical power cycle preceding the accident flight, and again when the PFD was started up for the accident flight. According to Avidyne, the attitude data, heading data, and HSI navigation data would have remained red-X’d if the PFD failed to properly align. The validity status of certain parameters (such as pitch, roll, and heading) was invalid for the entire duration of the power cycles.

Diagnostic parameters pertaining to the PFD’s Air Data System, which operated independently of the AHRS, indicated that the Air Data System was functioning normally. However, anomalies were found in the data (discussed below). According to Avidyne, the PFD would have continued to display altitude, airspeed and vertical speed on the display.

Although the AHRS did not align, the PFD’s logging function continued to record data normally, which included the values computed for the AHRS parameters (pitch and roll attitude, magnetic heading, body axis accelerations and rotation rates) although the PFD had flagged them as ‘invalid’. The sense (up/down, left/right, +/-) and trends appeared to generally agree with other independent data sources. Logging of the GPS data, navigational information, and pilot settings appeared to have functioned normally, and the data from these sources were unaffected by the PFD’s alignment status. A review of the GPS, Altitude and ATC radar data using a computer simulation model revealed discrepancies in the PFD recorded pitch, roll, and heading data.

Autopilot Data

With the PFD in an unaligned state, the only functional lateral autopilot mode is the NAV GPSS (GPS Steering) mode. In this mode, the autopilot uses inputs from the blind turn coordinator, and steering commands from the GPS receiver. This version of the PFD logging function records “snapshots” of the autopilot’s annunciator messages at discrete points in time. This occurred twice during the accident flight. At approximately 09:15:37, the “AP RDY” annunciator was recorded, indicating that the autopilot was not engaged in any mode. At approximately 09:19:42, at the end of the recording, the “NAV GPSS” annunciator was recorded. This indicates that the autopilot was engaged in the GPS Steering mode, and no vertical mode was engaged.

The autopilot was designed to limit the turn rate of the airplane to a maximum of 130% of a standard rate turn. According to the autopilot manufacturer, if the 130% limit were to be exceeded, the autopilot would attempt to reverse turn until the turn rate was reduced to 130% of standard rate. Additionally, the autopilot had a vertical acceleration limit of 0.6 G above or below the “steady state” of 1 G. If the sensed acceleration is greater than 0.6 G (in either direction, from 1 G), the autopilot will disengage the pitch servo temporarily, until sensed vertical acceleration are within these limits.

Air Data Anomalies Recorded On the Day of the Accident

The pressure altitude recorded by the PFD agreed with the pressure altitude recorded by the radar data. However, anomalies existed in the pressure altitude data that was recorded when the accident airplane was stationary on the ground, where a constant decreasing trend in altitude was observed. The trend was generally fairly slow, and differed slightly from one occurrence to the next. The first indication of this anomaly occurred on the morning of the accident during the power cycle preceding the accident flight (cycle 37), where the altitude slowly decreased about 51 feet in 284 seconds, at a relatively constant rate while the airplane was stationary. This occurred twice on the accident flight, although the rate was higher (decrease of about 54 feet in 166 seconds). Additionally, when the airplane began to taxi during the accident flight, the pressure altitude suddenly “spiked” by about 60 feet.

The cause of these anomalies was not determined, and review of the recorded data revealed that they did not occur in any of the other recorded data sets.

PFD’s Failure to Align

The PFD failed to align twice on the day of the accident. In both cases, ten parameters (heading, pitch, roll, 3 axis of acceleration, all 3 rates (pitch, yaw, roll), and rate of turn) were marked as invalid and remained so for the duration of power cycles 37 and 38 (the accident flight). Additionally, in both power cycles, a heading flag and attitude flag remained “set” and the Multi Processing Unit (MPU) indicated that the Inertial Reference Unit (IRU) was “Erecting”. These three conditions remained until the end of each power cycle.

Power Cycle 37 began at about 08:49:10, and ended at 08:54:48 on the day of the accident. The pilot was on the phone with Potomac TRACON from 08:55:08 until 08:58:32 (During this time, he received his IFR clearance at 08:57:52 with a void time of 09:08:00). According to Avidyne, the failure of the PFD to align during cycle 37 was most likely due to motion detected (on the yaw axis) during the initial critical AHRS alignment period. The heading was flagged as invalid during this time, and according to Avidyne, the HSI would display a red-X. Under this condition, the PFD would remain unaligned indefinitely. This behavior was duplicated during the testing at Vero Beach, Florida in January 2008, and was observed during a startup of another unrelated airplane with the same make/model/revision of the PFD.

Review of the recorded data for Power Cycle 38 (the accident flight) revealed that this cycle began about 08:58:40. The data indicates that the engine power was advanced for the takeoff roll at 09:04:50. During the PFD startup for the accident flight, no appreciable motion was detected during the initial AHRS alignment period and the airplane began the takeoff roll at approximately 375 seconds PFD log time.

Additional details are provided in the docket of NTSB Case No. NYC07FA083. The report title is “PFD and MFD Non-volatile Memory Extraction.”

Historical Data Regarding PFD Startup

It was also revealed that if the airplane remained stationary for the entire PFD alignment process, it typically took about 166 seconds from the start of the PFD log file until the alignment completed. If the airplane moved during the allowable taxi period (which would have been indicated by an “OK TO TAXI” message on the PFD), the alignment process took longer. The amount of time until alignment in part depended on how long the motion or taxiing continued. This was confirmed by comparison to other power cycles from the accident airplane, including one with a similar taxi segment to the accident flight where the PFD completed alignment at PFD log time 416 seconds (which also was the longest time to taken to align that was in all of the recorded data sets).

ADDITIONAL INFORMATION

Reversionary Modes for the Avidyne FlightMax Entegra Integrated Flight Deck

Review of the Avidyne FlightMax Entegra Integrated Flight Deck system revealed that unlike some other manufacturer’s electronic display systems, no reversionary mode existed that would allow the pilot to transfer the information displayed on the PFD to the MFD. If a PFD screen became unreadable, failed, or a software or hardware malfunction occurred, the pilot would be forced to use the standby instruments and GPS units. The pilot would be unable to fly an ILS approach as the localizer and glide slope deviations would not be displayed.

Incidents, Reliability Data and Service History

Incidents

Several in-flight incidents with the Avidyne Entegra were reported to Safety Board investigators. For example, four red Xs appeared when one airplane was in IMC conditions, and others exhibited erroneous roll indications. Some were thought to be due to capacitor cracking. There were instances of screen flickering, intermittent connection, screen blanking, red Xs, small and large scale drifting, rolling, interrupted roll, and instances of roll rates estimated to be in excess of 360 degrees per minute.

Reliability

Information obtained from airplane manufactures show multiple in-service anomalies from the time on installation to 1000 hours of operation. These anomalies included but were not limited to, alignment failures, air data errors, display errors, problems with software, in-flight failure of the units, horizontal lines being displayed, magnetometers not communicating, pitch errors, command bar errors, ADHRS failures, blanking out, flickering, erratic displays, miscompare messages, X-outs, sound and or smoke, and erratic knob operation.

Review of the FAA’s Service Difficulty Reporting (SDR) system also revealed anomalies which included but were not limited to reports of smoke, pixilation, smearing, airspeed errors, altitude errors, X-outs, and intermittent operation. Time in operation ranged from a low of 15 hours of operation to a high of 1,009 hours of operation.

Service Alerts, Service Bulletins, Airworthiness Directives

Review of corrective actions related to Avidyne systems revealed the following regarding the Avidyne Entegra System: three Avidyne Service Alerts and one Mandatory Service Bulletin, one FAA Special Airworthiness Information Bulletin (SAIB) and one FAA Airworthiness Directive (AD) for 477 units. The AD required the pilot to be made aware of the reported erroneous indications. An alternate means of compliance (AMOC) was issued to terminate provisions of the AD if rework was provided by an Avidyne facility.

Additional details are provided in the docket of NTSB Case No. NYC07FA083. The report title is “Accident, Incident, Reliability Data and Service History of Avidyne Entegra System.”