Trouble in the Cockpit: Execuflight 1526 Part One
On the 10th of November 2015, Execuflight flight 1526 was a British Aerospace HS 127-700A chartered for a flight across Ohio from Dayton-Wright Brothers Airport in Dayton to Akron Fulton International Airport.
The British Aerospace 125 is a twin-engine mid-size corporate jet, designed by de Havilland as a small business jet (under the much cooler name of the DH125 Jet Dragon) and originally produced by Hawker Siddeley. The aircraft has been used by the RAF as a navigation trainer and by the USAF as a calibration aircraft. The series 700 has variants including a military version for RAF liaison aircraft and a maritime patrol aircraft with search radar and cameras.
The BAe 125 registration N237WR was equipped with a cockpit voice recorder but no flight data recorder; it’s not required for aircraft that have fewer than 10 passenger seats. N237WR was configured with eight passenger seats. This means that the re-creation of the flight is based solely on the sounds audible in the cockpit voice recorder and external information. Unfortunately, the quality of the CVR recording was bad. The pre-start checks include a quick test but only to make sure that it is physically working, not to check the recording levels. As it happens, an FAA inspector did a ramp check on the aircraft but, as there was no power, he couldn’t check the CVR.
The aircraft was booked for a 7-leg charter spanning two days, using the same crew for each leg. The trip began the day before, on the 9th of November 2015 at 06:50, when the aircraft departed Fort Lauderdale with seven passengers on board. They stopped at St Paul, Minnesota; Mooline, Illinois and St Louis, Missouri before ending their day at 19:55 in Cincinnati, Ohio.
The following day, they departed Cincinnati and arrived at Dayton after a half-hour flight. At Dayton, the captain filed an IFR flight plan departing 13:30 for Akron, Ohio. The flight plan showed a 34-minute flight cruising at 17,000 feet with a cruise speed of 382 knots. The captain filled both wing tanks and, at 13:49, he sent a ‘doors closed’ text message to the operator. Air Traffic Control issued their IFR clearance to Akron Fulton International Airport and, at 14:13 EST, the flight departed on runway 20.
They contacted Indianapolis Air Route Traffic Control Center (ARTCC) and the controller cleared the flight to its cruising level of 17,000 feet and to Akron via the HUUVR intersection.
Execuflight had an informal practice that the captain would act as Pilot Flying on any flights carrying “revenue passengers”; however on this day, the first officer was the Pilot Flying and the captain was the Pilot Monitoring.
As they prepared for the approach, the flight crew attempted to pick up the weather information at Akron. They didn’t tune the radio correctly and instead of Akron’s status, they received the weather for Fairfield County Airport in Lancaster, about 108 miles southwest of their destination.
After noting the (incorrect) weather, the first officer, who as the Pilot Flying would normally handle the approach briefing, said, “I’ll let you brief it to me.”
They discussed the localiser 25 approach at Akron. Here’s the key information for that approach.
- Final Approach Fix (FAF) minimum crossing altitude: 2,300 ft above mean sea level
- Minimum Descent Altitude (MDA): 1,540 ft above mean sea level
- Touchdown zone elevation (TDZE): 1,067 feet
- The minimum descent height above the runway 25 TDZE: 473 ft
Review of the instrument approach chart for the localizer 25 approach at AKR showed that the FAF was located at 4.8 nm DME, and the missed approach point was at 1.1 nm DME.
The Indianapolis ARTCC controller cleared the flight to cross the HUUVR intersection at 9,000 feet and then asked them to change frequency to Cleveland ARTCC. The crew checked in with Cleveland and then returned to their discussion of the localiser 25 approach. Before they could finish, a passenger came forward from the cabin to speak to the crew.
The flight was descending through 13,500 feet and the captain told the passenger that he could stay for a couple minutes but then he had to leave because “we cannot be distracted”.
I’m including as much as possible of the transcript of the cockpit conversation, with parentheses used to mark where the words were not clearly audible in the CVR playback and might be wrong. The only other real information we have is the radar returns, from which we can extrapolate the speed and descent of the aircraft as it approached Akron.
First Officer: Okay, so we go down twenty three then down to… (what’s the minimums)?
Captain: four seventy three.
They discussed the missed approach and then the cloud cover. At Fairfield County Airport, the clouds formed a broken ceiling of 1,100 feet above the ground and an overcast cloud layer at 1,800 feet above the ground.
First Officer: The minima for this approach [is] fifteen twenty… Which is ground? Where is the ground? Five oh one, right?
From the accident report:
The MDA for the localizer performance version of the AKR RNAV GPS 25 approach was 1,520 ft msl, and the height of the MDA above the TDZE for the lateral navigation version of the approach was 501 ft.
What this means is that the chart showed two ways of looking at the same approach. One had 1,520 feet above mean sea level as the MDA (Minimum Descent Altitude). The second showed 501 feet above the ground as the MDA: in other words, one was the altitude and one was the height. The elevation of the airfield was just over 1,000 feet above mean sea level, so there’s a difference of just over 1,000 feet between the two figures, even though effectively they are used for the same thing: the specified altitude or height below which the flight crew should not descend without being in sight of the runway.
Forgive me for going over this at length but I find this usage of MDA to be deeply confusing. We’ve had some discussions in the comments about Minimum Descent Altitude vs Minimum Descent Height and I have to admit, it’s making my brain ache to read this report which repeatedly refers to height as altitude in the context of the MDA. Certainly, it seems like this is a poster-child for why it is important to specify, even in acronyms, whether you are discussing altitude above the airport (above mean sea level, or QNH in the UK where I trained) or height (above the ground, or QFE in the UK).
From a personal point of view, if I were the Pilot Flying and mixing up 1,520 feet above mean sea level and 501 feet above the ground in a single conversation about the MDA, it probably means I’m already halfway to becoming a crash statistic myself.
First Officer: Which is ground? Where is the ground? Five oh one, right?
No, that’s not right. Five oh one, or 501 feet is the minimum height above the ground that they needed to be for that approach. While he (incorrectly) answered his own question, the aircraft descended through FL10 (10,000 feet) travelling at about 298 knots. The aircraft should have been going no more than 250 knots once travelling under 10,000 feet.
They continued to discuss how low the overcast clouds were.
First Officer: “Yeah, I understand. But we can shoot it. We can shoot it because the overcast [unintelligible] reporting [unintelligible] eight hundred.”
First Officer: “The cloud base is from the ground. From the ground do we get minimums for us?”
They played the automated weather at Akron, which reported an overcast ceiling of 600 feet above the ground, with visiblity of 1½ miles (2.4 km) in mist. But the flight crew were distracted.
The Cleveland ARTCC controller instructed the flight to change to Akron approach.
The first officer contacted Akron approach and reported that they were level at 9,000 feet above mean sea level over the HUUVR intersection. The controller told the aircraft to fly a heading of 65° and to expect localizer 25 approach.
The controller then asked whether they had the weather at Akron.
First Officer: “We are in the process of copying the weather.”
Where I come from, that means “No.” But to be fair, the captain had been listening to the recording, which he repeated. Then the flight crew discussed the visibility. The required visibility minimum for the aircraft’s approach category was 1¼ miles.
Captain: One and half mile visibility, overcast at six hundred. Alright, we are visibility, we got it.
The next exchange is not clear on the CVR but went something like this:
Captain: Did you do my approach (brief)? [unintelligible] (We gotta go somewhere else, right?) [unintelligible]
First Officer: [unintelligible]
Captain : If you say that… I might be wrong. I’m not sure.
It’s not clear exactly what was said but the Captain’s tone is odd. Execuflight’s policy was that generally, the captain should act as Pilot Flying on all flights carrying revenue passengers. Not only had the captain passed this responsibility to his first officer, he also failed to insist that they should consider a possible divert to an airfield with better weather, despite his misgivings.
First Officer: [unintelligible]. The minima is five hundred and ten. [unintelligible] minima…
Captain: Four eighty, four eighty.
First Officer: Four seventy three.
I couldn’t make sense of this one at all. I scanned over my notes for 473 to see that it is the “height above the TDZE of the MDA for the localizer 25 approach” or what I would call the minimum descent height over the touchdown zone. But frankly, by this point in the narrative, I’m at a loss as to which heights are what and I strongly suspect the first officer felt the same. Frankly, I don’t think 510 ever comes up on the approach at all, it’s just a random number.
Meanwhile, the approach controller instructed the flight crew to reduce speed to 200 knots and descent to 4,000 feet msl. Then he contacted them again to say that they were behind a slower aircraft on approach (an instrument training flight in a single engine aircraft) and to reduce speed to 170 knots with a descent to 3,000 feet msl. Finally, the controller instructed them to join the localizer course for runway 25.
The aircraft reached 3,000 feet msl and levelled off.
First Officer: I will….try to drag every (thing).
This means nothing to me but the report says that it meant he planned to begin configuring the aircraft for landing by extending the flaps and landing gear.
Captain: Oh we got…we got… we got nine degrees pitch up.
He’s saying that the first officer was flying with a high pitch attitude but gosh, it makes me realise how much easier this is when we have the data from the FDR to tell us what the aircraft is doing!
As it is, we’re reliant on sound: the CVR recorded ‘increased noise consistent with a power increase and then the sound of a thump followed by noise similar to landing extension’. Unfortunately, from this point onwards the noise from the extended gear obscured the already not-very-good recording from the CVR and so it becomes more and more difficult to recreate what was happening in the cockpit.
Captain: Did you hear what he said? There is an airplane on the approach. (He is) slower than us. He hasn’t cancelled. We don’t know if he’s on the ground.
Then he complains again about the pitch attitude.
Captain: You need to (look). You need to… I mean, we were were flying like (one thirty
nine). Nine degrees pitch up.
Based on the radar returns, investigators believe that, during this time, the aircraft pitch increased from about 5° to 12° nose up. Over the same period, the airspeed slowed from 150 knots to about 125.
The aircraft was about four nautical miles from the Final Approach Fix for the localiser 25 approach. The controller contacted the flight crew to say that the slower aircraft ahead had cancelled its IFR flight plan and he cleared them for the localiser approach. The captain acknowledged the clearance and confirmed that they were established on the localiser.
The slower aircraft ahead was a training flight. Afterwards, that flight crew reported that they broke out of the clouds about forty feet above the MDA of 1,540 feet amsl. They levelled out at the MDA at three nautical miles out, where they had visual contact with the ground but they couldn’t see the runway ahead. They activated the PAPI and runway lights to high intensity. The runway PAPI lights came into view when they were about 2.3 nautical miles out.
The FAF was about 4.8 nautical miles and the missed approach point was at 1.1 nautical miles. Normally, the PAPI lights are visible from about 5 miles during the day and up to 20 miles at night.
Back to the Execuflight cockpit, the captain and the first officer were still arguing. They were cleared to descend to the FAF crossing altitude of 2,300 feet amsl but they remained at 3,000 feet for about two minutes.
Captain: Look, you’re going one twenty. You can’t keep decreasing your speed [unintelligible].
First Officer: No. One tw– how do you get one twenty?
Captain: That’s what I’m saying. If you keep decreasing your speed–
First Officer: But why?
Captain: Because we’re going to stall. I don’t want to sta–
The controller interrupted them to change to the local advisory frequency. The captain did so and made a position report.
The pilot of the instrument training flight then spoke. “Hey guys. Ah, we just landed on the loc and broke out right at minimums, (right at a) mile.”
Captain: Appreciate it.
First Officer: Full flaps.
Full flaps is 45°. The standard approach profile was 25° flaps until the minimum descent alttitude, only applying full flaps once the runway was in sight. The reason for this is so that the aircraft is able to climb away safely if they have to go around. Having heard that the previous aircraft only just broke out of the clouds at the last minute, there’s a high chance that they will need to go around so it’s a particularly odd time to decide to set full flaps.
Captain (reciting the landing checklist): Gear down. Before landing. Three lights. One and…
He does not appear to be bothered by the full flaps.
The aircraft’s airspeed, which had stablised at about 130 knots, began to decrease again. The first officer reduced the power and the aircraft began to descend. They were just crossing the Final Approach Fix.
First Officer: Alright, we got to minimums.
In other words, they can continue to the MDA. At this point, the aircraft was passing through 2,700 feet above mean sea level (400 feet above the Final Approach Fix minimum crossing altitude) and was travelling at around 109 knots. They are too high.
The rate of descent began to increase rapidly. As the aircraft reached 2,300 feet, the descent rate was about 2,000 feet per minute with an airspeed of around 118 knots. The captain calls out the too-fast descent.
Captain: On localizer. You’re diving. You’re diving. Don’t dive! Two thousand feet per minute, buddy.
First Officer: Yeah.
Captain: Two thousand feet per minu–Don’t go two thousand feet per minute.
Yeah, don’t do that. The ‘normal’ descent in that aircraft on that approach would be one thousand feet per minute; however that rate of descent was not going to get them to the MDA in the distance they had left. It seems likely that the first officer was intentionally expediting their descent to ensure that they would be able to break through ‘just in time’ like the previous flight had.
Captain: Don’t go two thousand feet per minute.
This seems to be an odd thing to repeat. I’m going out on a limb here: it seems very laid-back or careful phrasing for the captain of the flight. Personally, if I’m ever in that position, I’d like the other person in the cockpit to be crystal clear about my error. REDUCE DESCENT NOW! Or maybe even I HAVE CONTROL!
But then, politeness and social tact have never been my forte.
Captain: When you are fifteen hundred feet above the ground. Or minimums.
I’m not sure of my interpretation of this. He might mean, ‘Don’t descend so quickly when you are this close to terrain,’ which would be a reasonable thing to say, although again, a bit oblique for my tastes. Or he may have been continuing to speak when he realised they had reached the MDA and so he interrupted himself to say they were at the MDA.
Either way, they reached the MDA. They were travelling at 113 knots with a reasonable descent rate of about 830 feet per minute. Unfortunately, the aircraft continued its descent.
A confirmation that the ground was in sight, I guess?
Captain: Keep going.
Captain: Okay, level off, guy.
As he spoke, there was a loud rattling sound: the stick shaker had activated to warn of an impending stall. It sounds like he did level off, but without adding power.
Then the Ground Proximity Warning System kicked in. PULL UP.
And that is the end of the recording. The aircraft crashed through trees and into an apartment building, where it burst into flames. It was just twenty-four seconds after the captain had repeated “Don’t go two thousand feet per minute.” The first officer had slowed his descent, but even 830 feet per minute is too fast if you don’t know where the ground is.
An aircraft security camera filmed the aircraft as it appeared over the trees in a left-wing-down attitude about 1.8 nautical miles from the approach end of runway 25. The aircraft passed out of the camera’s view but the explosion and postcrash fire were still visible.
Pieces of the left aileron and an outboard portion of the left wing were located in an area of ground scarring in the front yard. The airplane traveled through the building and came to rest on an embankment located behind the building.
The left main landing gear was in the remains of the apartment building. The right main landing gear were behind the building, before the embankment. The burned remains of the fuselage and empennage were on the embankment, along with most of the right wing, the nose landing gear, both engines and the APU. The investigators were able to confirm that at the time of impact, the landing gear was down and locked and the flaps were extended to 45°. Both engines were operating and ingested building insulation and soil during the crash.
The Summit County Medical Examiner’s Office performed autopsies on the captain, the first officer and the seven passengers. The medical examiner determined that the cause of death for both pilots was “inhalation of products of combustion and thermal injury.” According to the autopsy reports, no significant natural disease was identified in either pilot. Review of FAA medical certification records showed that neither pilot had reported any significant medical conditions or the use of any medications.
The medical examiner determined that the cause of death for five passengers was “blunt force trauma,” and the cause of death for two passengers was “blunt force trauma…with inhalation of products of combustion.”
The ExecuFlight CEO expressed his shock and confusion at what had happened.
Planes just generally don’t fall out of the sky. I can tell you that there were very well seasoned pilots, both of them. They like to fly together. We monitor the flights leg by leg since it started and it’s typical for them to give us a doors open, doors closed message, we’ve got them all.
Some pieces of this are already obvious and some of the conversation will remain a mystery. But I’ve gone on too long already.
Next week I’ll take a look at the background; there’s still quite a bit of ground to cover to make sense of this. In the meantime, I’ll be interested to hear your opinion so far in the comments.