Avalon, CA, USA
N7133G
CESSNA 172
The private pilot and non-pilot rated passenger departed for a personal flight to an island airport located on top of a plateau. While on final approach for landing, the airplane descended below the elevation of the runway threshold. The pilot attempted to conduct a go-around but was unable to prevent a collision with the rising terrain. Detailed examination of the airframe and engine did not reveal evidence of any pre-impact mechanical deficiencies or failures that would have precluded normal operation. The airport's website contained information for pilots about its unique operational hazards. The website explicitly warned that there were no visual cues for altitude reference on approach, that there was usually a strong downdraft near the approach end of the runway due to the surrounding terrain and prevailing winds, and that the upslope of the runway could cause approach and flare difficulties for inexperienced pilots. The website further stated that most flying clubs required pilots flying into the airport for the first time to be accompanied by a flight instructor or another pilot familiar with the airport. The pilot reported that the accident flight was his first experience flying to that airport, and that neither his co-owners of the airplane, nor his insurance company, required any checkout flight to that airport. He reported that he was only vaguely aware of the visual illusions associated with the landing approach; and that he was unaware of, and never saw or used, the pulsating visual approach slope indicator (PVASI) with which the runway was equipped. Review of onboard GPS data revealed that the pilot flew a straight-in approach, instead of the normal and recommended right traffic pattern. The airplane joined the final approach course about 1.4 miles from the runway threshold and about 100 ft below the nominal approach path slope. The airplane descended farther below the nominal approach path and remained in the PVASI flashing red (well below course) indication zone for the entire approach. The pilot initiated the go-around about 8 seconds before impact, as the airplane descended below the elevation of the threshold. The pilot's incomplete preparations for the flight, particularly with regard to the airport's peculiarities and associated hazards, resulted in the pilot conducting an inordinately low final approach. Had the pilot flown the recommended traffic pattern instead of a straight-in approach, he would have provided himself with another opportunity to detect the airport's unusual characteristics and conduct his final approach accordingly. Finally, ground and wind speed data suggest that the airplane was near or at the extreme low end of its normal approach speed range just before the go-around. In combination, these factors placed the airplane in a position and energy state from which recovery was difficult or impossible once the airplane encountered the known downdraft phenomenon just short of the runway threshold.
HISTORY OF FLIGHTOn April 17, 2016, about 1629 Pacific daylight time, a Cessna 172K, N7133G, was destroyed when it impacted terrain during a landing attempt at Airport in the Sky (AVX), Santa Catalina Island/Avalon, California. The private pilot and his passenger received serious injuries. The personal flight was conducted under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed. AVX is situated in rugged terrain, atop a mountain that was leveled off to construct the airport. Under the approach path to runway 22, the terrain rises steeply to the airport elevation and runway threshold. According to a pilot and his friend who were standing at the airport watching the airplane arrive, when on final approach to runway 22, it appeared low, and possibly slow as well. The pilot-witness waited for the engine sound to increase to indicate a climb attempt, but he did not hear that. As the airplane began descending below the local horizon, the witnesses observed it enter a very steep right-wing down bank, and disappear from view. They listened and watched for indication of either impact or a successful escape, but heard and saw nothing to indicate either. They then notified the airport operations staff that they believed the airplane had crashed. The two witnesses departed soon thereafter in another Cessna 172 (N365ES), and conducted a brief and unsuccessful visual scan for the airplane. About 2 minutes later, they heard a radio call on the AVX common traffic advisory frequency (CTAF) to another airplane, indicating that the US Coast Guard had detected an ELT signal about 0.7 miles southeast of the airport. The pilot-witness announced that he was returning to the area to conduct a visual aerial search, and that he suspected that the accident site was north of the airport. Shortly thereafter, the pilot-witness and his passenger located the wreckage, and guided ground personnel to it. They were also successful in establishing radio communications with the accident pilot, who was using his handheld aviation transceiver. According to the accident pilot, he was approaching runway 22 for a landing when he determined that the airplane was too low. He attempted to climb and turn to avoid terrain. The airplane banked sharply to the right, and struck terrain shortly thereafter. The airplane came to rest nearly inverted, and the pilot was able to exit the airplane. His passenger remained trapped in the wreckage, but there was no fire. First responders extracted the passenger, and both she and the pilot were airlifted to a mainland hospital. The wreckage was recovered to a secure facility for investigative examination. PERSONNEL INFORMATIONThe pilot held a private pilot certificate with an instrument rating. He was one of five co-owners of the airplane, and had purchased his share about 2 months before the accident, in late February 2016. The pilot reported that as of the date of the accident, he had about 174 hours total flight experience, including about 84 hours in the accident airplane make and model. His most recent flight review was completed in November 2015, and his most recent Federal Aviation Administration (FAA) third-class medical certificate was issued in April 2013. AIRCRAFT INFORMATIONFAA information indicated that the airplane was manufactured in 1969, and was equipped with a Lycoming O-320 series engine. A review of airplane maintenance records revealed that the most recent annual inspection was completed in January 2016. At that time, the airplane had a total time in service of about 4,952 hours. The maintenance records did not reveal any unusual or repetitive entries, or any recent engine power-related entries. In November 2014, a 406 MHz emergency locator transmitter (ELT) was installed in the airplane. METEOROLOGICAL INFORMATIONThe 1551 AVX automated weather observation included winds from 260º at 11 knots, visibility 10 miles, clear skies, temperature 24º C, dew point 0º C, and an altimeter setting of 30.02 inches of mercury. The 1651 AVX automated observation was very similar, but included winds from 250º at 14 knots. AIRPORT INFORMATIONFAA information indicated that the airplane was manufactured in 1969, and was equipped with a Lycoming O-320 series engine. A review of airplane maintenance records revealed that the most recent annual inspection was completed in January 2016. At that time, the airplane had a total time in service of about 4,952 hours. The maintenance records did not reveal any unusual or repetitive entries, or any recent engine power-related entries. In November 2014, a 406 MHz emergency locator transmitter (ELT) was installed in the airplane. WRECKAGE AND IMPACT INFORMATIONThe wreckage was located in a ravine, approximately 400 feet north-northwest of, and 150 feet below, the runway 22 threshold. The impact location and wreckage area were situated on steeply sloping terrain; ground scars and the final resting point indicated that the airplane slid and/or tumbled downhill from the impact point. The wreckage came to rest inverted, against an outcrop of small trees. The right wing was fracture-separated from the fuselage, and the fuselage was significantly torn, crumpled, and otherwise deformed. Detailed examination of the airframe and engine did not reveal any pre-impact mechanical deficiencies or failures that would have precluded continued normal operation and flight. Damage signatures were consistent with the airplane striking terrain in a right wing down, nose-first attitude. The cabin structure retained most of its original occupiable volume, with the exception of the two cockpit footwells. The primary cabin impact damage and deformation was consistent with impact loads applied from the lower forward right side. Additional damage, particularly to the aft fuselage and empennage, was consistent with the airplane tumbling and/or sliding down the steeply-sloped terrain at the accident site. The fuel selector was found set to the left tank, the flaps were set to about 20º, and the elevator trim was approximately neutral: all of these settings are consistent with those of a normal final approach. Propeller damage was consistent with the engine developing power at the time of impact. Refer to the public docket for this accident for detailed information. An Appareo brand Stratus 2S GPS device was recovered from the wreckage. The pilot reported that he used the device during the accident flight, so it was sent to the NTSB Recorders Laboratory in Washington DC for data download. ADDITIONAL INFORMATIONPilot's Flight Preparations and Recollections In a telephone interview with the NTSB investigator, the pilot reported that he had never flown into AVX before. Neither the co-owners nor the insurer of the airplane required or suggested any AVX-specific checkout or dual flight prior to solo flights there. In preparation for the flight, the pilot conducted some research about AVX by speaking with some fellow pilots, and reading on the internet. From that research he learned/recalled that the runway was "bowed," meaning it crested and, after touchdown, appeared shorter than it actually was. The pilot also stated that he learned that there were some "optical illusions" associated with the runway, but other than the "bowed" effect, he was unable to be more specific about what those illusions were. When the pilot was asked whether, as part of his approach path alignment, he saw or used the PVASI, and what its indications were, he responded that he was unaware of its existence, and did not recall seeing or using any light-based approach slope indicators. In his discussion shortly after the accident with a sheriff who was a first responder, the pilot reported that when on the final approach, he realized that he was too low and added power to climb. He stated that the right wing went down, and that he "added rudder" but that rudder application was ineffective. The pilot was able to extract himself from the wreckage, and used his handheld aviation-frequency transceiver to attempt to call for help. Those communications attempts were unsuccessful until N365ES returned and visually located the wreckage. Accident Notification and Location Activities The two witnesses from N365ES who believed that N7133G had crashed could not be certain of the accident due their lack of any definitive aural or visual evidence. Their notification to the airport operations staff prompted that individual to conduct a brief visual search, but that search was unsuccessful. At 1629, which was less than a minute after the accident, the first signal from the airplane's ELT was received by one of the satellites in the detection network. The signal provided the airplane identification, but was insufficient to enable a position solution. Due to the lack of any position information, personnel at the Air Force Rescue Coordination Center (AFRCC) in Florida had to wait for a second detection before they could notify the geographically appropriate search and rescue agency. According to AFRCC personnel, they then began attempting to contact the airplane owners listed on the ELT registration by telephone, but were unsuccessful. Although the airplane was co-owned by five persons, the ELT registration/contact list only contained three names and phone numbers. One of those persons had sold his share to the accident pilot about 6 weeks prior, and the phone number listed for another co-owner was incorrect. At 1647, the third co-owner (initials "FQ") on the list was telephoned by the AFRCC, but FQ was unable to take the call because he was working. The next satellite detection of the ELT occurred at 1649, and enabled the first position solution. That solution indicated that the accident site was situated about 4,300 feet southeast of AVX, which was about 5,300 feet from the actual accident location. Based on that position solution, AFRCC notified the United States Coast Guard (USCG) District 11 Rescue Coordination Center (RCC), whose personnel made contact with the AVX operations staff, who in turn used CTAF to contact an inbound airplane, and request search assistance. That radio call also prompted the pilot of N365ES to turn back towards AVX, and execute an aerial visual search. At 1658, the USCG RCC made telephone contact with co-owner FQ, and notified him that the airplane's ELT signal had been detected. FQ placed telephone calls to the other four co-owners, but did not reach any of them. Shortly thereafter FQ determined that the accident pilot had departed LGB, with an intended destination of Catalina/AVX. About 1710, the local Los Angeles County Sheriff office was notified of a possible aircraft accident, and that office began a coordinated search and rescue response. A third satellite detection occurred at 1723, and the data from that and the previous detection enabled a second position solution. The revised position was just north of AVX, and was situated about 1,100 feet from the actual accident location. That revised position information was communicated to the USCG, and then to persons directly involved in the search. At an unknown time, the pilot and passenger of N365ES visually located the wreckage, and guided first responders to the scene. Airplane Weight and Balance Information Review of available information indicated that the airplane was within its weight and balance limits for the departure, flight, and accident. The airplane gross weight was estimated to be about 1,890 lbs at the time of the accident, which was about 410 lbs below the maximum allowable value of 2,300 lbs. Airplane Performance Information The airplane manufacturer's Owners' Manual (OM) provided various guidance elements in several sections throughout the document. In the checklist-style "Normal Procedures section, the OM specified approach speeds of "70 to 80 MPH (flaps up), 65 to 75 MPH (flaps down)." The only landing performance data was for 40º flaps, and an approach speed of 69 "IAS [indicated air speed] MPH.," A "Performance Data" sheet provided by an airplane co-owner, and which was reportedly in the airplane, cited an approach speed of "70 to 80 MPH," but did not specify a flap setting. In his written communications with the NTSB, the pilot stated that he used "20 degrees - 65kts." The units on the outer/primary ring of the airspeed indicator were presented in mph, but were not explicitly labeled as such. The inner ring units were presented in knots, and explicitly labeled as such. The "Balked Landing (Go Around)" subsection in the OM checklist section checklist cited a maximum flap setting of 20º, and specified retraction of the flaps (from 20º) "upon reaching an airspeed of approximately 65 MPH." The expanded balked landing subsection stated "If obstacles must be cleared during the go-around climb, leave the wing flaps in the 10º to 20º range until the obstacles are cleared." Obstruction clearance guidance in the OM specified a climb speed of 68 mph "with flaps retracted." The co-owner "Performance Data" sheet specified a best angle climb speed of 68 mph, but did not cite any flap setting. The pilot did not report what speed or flap setting he used for his go-around attempt, but as noted previously, the flaps were found at their apparent approach setting of about 20º. For reference purposes, the OM stall speeds for flaps 10º and bank angles of 0º, 20º, 40º and 60º are 52, 54, 59 and 74 mph CAS respectively. The OM only presents stall speeds for the maximum gross weight of 2,300 lbs, and for flap settings of 0º, 10º and 40º. Due to the IAS-CAS differences, combined with the facts that the airplane weighed less than its maximum allowable weight, and that the flaps were set to 20º, the actual IAS stall speeds, as estimated by the NTSB, would have been about 1 to 2 mph below the above-cited OM values. Appareo Stratus 2S Flight Data The recovered GPS device contained the accident flight data, and the data was successfully downloaded. The GPS data file for the flight began when the airplane was parked in its spot at Long Beach Airport (LGB), Long Beach, CA, and ended at the accident location. The data is consistent with the pilot stopping to conduct an engine run-up, and then departing on LGB runway 25R. The airplane flew a right downwind leg until it was just east of LGB, and then turned approximately south towards AVX. The pilot reported that while utilizing ATC flight following services, the controllers assigned him some headings and altitudes enroute for traffic avoidance purposes. When the airplane was about 10 miles from the mainland shore, it began an essentially straight and direct track towards AVX. When the airplane was approximately 2.5 miles from the AVX runway 22 threshold, the track turned more southbound, and then southwest to join the extended runway centerline, about 1.4 miles from the threshold. The airplane then tracked directly towards the runway until the pilot attempted to go-around, when he deviated to the right. Flight duration from takeoff to accident was approximately 24 minutes. About 70 seconds prior to the accident, the airplane joined the AVX runway 22 final approach course, at a GPS altitude of about 2,000 feet. At that location, the PVASI nominal approach path altitude was approximately 2,100 feet, and the airplane was in the zone where the pilot would have seen the pulsating red light, indicating that he was well below the desired approach path. The airplane descended away from the nominal approach path, and most of the rest of the approach remained in the flashing red indication zone. For the final mile of the approach, the airplane was situated approximately 150 feet below the nominal PVASI approach path. When the airplane was about 1/2 mile from the threshold, it descended below the lower limit of the flashing red indication zone, which represented an approach slope of 0.15 degrees. The GPS-derived groundspeed of the airplane was about 115 mph when it joined the final approach course. The groundspeed decreased steadily to about 40 mph, until about 8 seconds prior to the accident, when it began increasing steadily to about 63 mph, reached immediately before the accident. The speed increase was approximately coi
The pilot's failure to maintain a proper approach path on landing because he failed to familiarize himself with the airport's unique approach hazards and recommended procedures before the flight. Also causal was the pilot's failure to recognize the airplane's improper approach and to execute a go-around in a timely manner.
Source: NTSB Aviation Accident Database
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