Description

On 15 March 2012, a Convair 440 Freighter (N153JR) being operated by Fresh Air on a contract cargo flight from San Juan Puerto Rico to St Maarten in day Visual Meteorological Conditions (VMC) on a Visual Flight Rules (VFR) flight plan declared an emergency shortly after take off and requested an immediate return to land on the reciprocal runway but crashed into terrain as the low level turn was being completed, destroying the aircraft and killing the two pilots.

Investigation

An Investigation was carried out by the National Transportation Safety Board (USA) (NTSB). The accident aircraft was not equipped with an Flight Data Recorder (FDR) or Cockpit Voice Recorder (CVR) nor was it required to be, but radar recordings of the aircraft were available.

The aircraft was being operated under FAA Part 125 regulations which are applicable to 'private carriage' of goods or passengers by 'large' aircraft, defined as having either a seating capacity of 20 or more or a maximum payload capacity of 6000lb (2722kg) or more.

The 65 year old aircraft commander had about 9000 hours experience on the Convair 340/440 from 1977 onwards. He was the co-owner of the Operator, one of their two full time Captains and the Company's only "check airman". The 44 year old First Officer had 700 hours experience on the Convair 340/440 and 2716 hours in total. The available evidence suggested that the commander had been PF prior to the emergency arising but that a some undetermined point prior to the subsequent impact, the First Officer had taken this role.

It was established that a VFR flight plan had been filed and the cargo loaded was 'bread products'. One minute and 42 seconds after the aircraft became airborne from runway 10, the First Officer declared an emergency to ATC following evidence of fire in the fright engine exhaust duct. The Captain then requested a left turn back towards the airport which was approved and clearance to land on the reciprocal runway direction was issued. After reaching a maximum altitude of 935 feet whilst in a 30° banked turn left some 2.5 minutes after becoming airborne, the aircraft continued to position for the return (see the annotated diagram below) but airspeed subsequently reduced and at the last radar return at an altitude of just 110 feet was estimated as just 88 knots, a speed some 9 knots below the published stall speed and close to Vmca which would have increased significantly as the crew made a turn 'into' the inoperative engine in the final seconds of the flight.

The right wingtip struck trees at a bank angle of "about 39° right wing down and part broke off before the rest of the aircraft crashed into the nearby lagoon". Although the left engine throttle control was found in the fully open position and the right engine throttle control was found in the closed position, examination of the wreckage disclosed that at impact, the left propeller had been feathered whereas the right propeller pitch setting was indicative of that used for high power during take off.

Although there was no sign of any mechanical failures which would have prevented normal engine function, it was clear that the effects of uncontained fire originating in the exhaust duct had led to the decision to shut down the right hand engine. Corresponding damage was found to the airframe at the right wing rear spar and the right engine nacelle aft of the power section with all of this fire and thermal damage out of range of the installed fire detection/warning system. Although the Investigation was unable to determine the exact location of the ignition source, it appeared to have been in the vicinity of the junction between the augmentor assemblies and exhaust muffler assembly. The Investigation was informed by mechanics familiar with the type of aircraft that exhaust fires fed by oil or fuel leaks into the engine exhaust duct did occur in the augmentors on this type of aircraft. Although in normal conditions, such fire would be exhausted overboard without damage to the aircraft, fire leaking out of the augmentor assembly at the junction with the muffler assembly would have produced the damage that was found on the accident aircraft.

It was established that the accident aircraft had originally been manufactured in 1953 as a CV-340 and subsequently - at an undetermined date - converted to a CV-440. In the absence of any loadsheet or equivalent documentation, the Investigation estimated that the Take Off Weight prior the accident had been 21550 kg including cargo weighing 5460kg compared to the MTOW of 21773 kg. However, this weight required that both the Water Meth and Autofeather systems were operative whereas the evidence indicated that neither were and that this was routinely the case at the Operator.

It was noted that the effect of the overweight take off would have been immediately apparent when either engine was shut down and would have made handling of the aircraft during the attempted turn back an extremely 'delicate' business if loss of control was to be avoided. In respect of the finding of the wrong engine having been feathered at the point of impact, it was concluded that this "likely occurred late in the accident sequence because the flight profile indicates that at least one engine was generating thrust until near the end of the flight".

Three Safety Issues relating to the oversight of the Operation by the Federal Aviation Administration (FAA) were identified as a result of the Investigation as follows:

• Inadequate Federal Aviation Administration (FAA) oversight of Part 125 operations. The investigation found that many of the operator’s operation and maintenance records were incomplete or nonexistent. The FAA requires annual inspections of each certificated operator, including a review of pilot records, pilot currency, and aircraft maintenance. During the last documented main base inspection, which occurred just over 2 months before the accident, the principal operations inspector (POI) should have discovered the recordkeeping discrepancies and instructed the operator to verify the captain’s currency; however, he did not. Likewise, the principal maintenance inspector and the principal avionics inspector should have discovered Fresh Air’s deficient aircraft maintenance recordkeeping during the last documented aircraft records inspection, which was conducted 7 days before the accident, or during any of the six inspections conducted in the year before the accident; however, they did not. Further, the National Transportation Safety Board (NTSB) found evidence suggesting that FAA oversight of Part 125 operations was not seen as a priority. Fresh Air’s POI told investigators that Part 125 was generally “a GA [general aviation] operation,” not an air carrier operation. While most of its flights were relatively close to San Juan, Fresh Air’s FAA-approved operations specifications (OpsSpecs) authorized it to operate commercially over the 48 contiguous states, meriting far more scrutiny than “a GA operation.” Multiple FAA inspectors failed to perform effective, basic oversight of Fresh Air, possibly due to a belief that Part 125 operations merit less scrutiny than Part 121 and Part 135 operations, and despite the fact that Fresh Air’s airplanes fly over populated areas within the national airspace system.

• Inadequate evaluation of Fresh Air’s compliance with FAA-approved procedures. The investigation revealed the FAA’s failure to detect and address discrepancies between Fresh Air’s approved procedures and its operations, including cargo loading, pilot currency, company recordkeeping, and pilot evaluation. For example, Fresh Air pilots were operating the airplane with the autofeather and antidetonation injection systems off, yet using a higher gross takeoff weight than permitted with these systems off, contrary to the FAA-approved airplane flight manual. Because the POI had never directly observed Fresh Air’s operation, he was unaware that the airplanes were being operated contrary to the limitations outlined in the airplane flight manual.

• Evaluation of Part 125 pilots using another operator’s OpsSpecs. The investigation revealed confusion among operators and FAA personnel regarding the applicable OpsSpecs that check airmen must use during certain checkrides. While it (is) unlikely (that it) affected the Captain’s capability to handle the accident, his competency check was not necessarily conducted using Fresh Air’s OpsSpecs or operations manual. While the investigation could not determine under which company’s OpsSpecs and operations manual the Captain was evaluated for the Convair, the Captain’s DC-4 evaluation was conducted using another company’s OpsSpecs and operations manual.

The Investigation determined that the Probable Cause of the accident was “the flight crew’s failure to maintain adequate airspeed after shutting down the right engine due to an in-flight fire in one of the right augmentors. The failure to maintain airspeed resulted in either an aerodynamic stall or a loss of directional control".

Three Safety Recommendations were made as a result of the Investigation as follows:

• that the FAA should evaluate the effectiveness of your 14 Code of Federal Regulations (CFR) Part 125 oversight program and ensure that 14 CFR Part 125 operations are conducted at the same level of safety as that of Parts 121 and 135. [A-14-110]

• that the FAA should require all principal operations inspectors of 14 Code of Federal Regulations Part 125 certificate holders to conduct at least one en route inspection annually on each airplane type operated by the certificate holder. [A-14-111]

• that the FAA should require check airmen who evaluate pilots under the 14 Code of Federal Regulations Part 125 lateral moves provision to use the operations specifications of the certificate holder employing the pilot who is receiving the proficiency check to ensure a proper evaluation of the pilot’s knowledge of those specifications. [A-14-112]

The Final Report was adopted by the NTSB on 17 November 2014.

Further Reading

• Loss of Control
• Fire in the Air
• Engine/APU on Fire: Guidance for Controllers
• Aircraft Fire Extinguishing Systems
• Engine Failure After TakeOff - Light Twin Engine Aircraft
• Safety Oversight